Immediately Dangerous to Life or Health (IDLH) Value Profile:  1,3-Butadiene

Basis for IDLH value: Despite the availability of toxicity data capable of being used to calculate health-based estimates for 1,3-butadiene (see Tables 4 and 5), the majority of these estimates are greater than 10% of the lower explosive limit (>10% LEL). NIOSH has adopted a threshold of 10% LEL as a default basis for the IDLH values based on explosivity concerns. Since safety considerations related to the potential hazard of explosion must be taken into account, the IDLH value is set at the 10% LEL for 1,3-butadiene of 2,000 ppm.